(1) Field of the Invention
This application claims priority from German application number DE 103 60 110.4 filed on Dec. 12, 2003, which is hereby incorporated by reference.
The invention relates to members capable of being temperature controlled such as they can be used with most various applications. Thus, tempering can be carried out in the form of cooling such members. However, it is also possible for the correspondingly designed members to be heated, and allowed to perform pre-heating up to a defined temperature, respectively.
The temperable members according to the invention can be used preferably as tools for different molding processes to manufacture workpieces. So, the members according to the invention are allowed to be core molds, injection molding or die casting tools, foaming tools, blow molds, dies, but also forming tools. With such tools it is then allowed for the workpieces to be manufactured into shape or machined from the most various materials such as plastics, metals or sand cores.
(2) Description of Related Art.
With the various molding processes, different temperatures on the corresponding tools are to be taken into account. In this connection, the respective molding process and the adequate material to be used for manufacturing workpieces do not only play a part, however, quite often the geometric design of the workpieces and accordingly of the tools as well is also to be taken into account, which frequently results in considerable temperature gradients on such tools.
Thus, with such tools it happens quite often that in specific areas, there are volumes of material being distinctly greater than in other volume areas of such tools due to the geometrical design required there, and under the present temperatures and forces during the respective molding process. These volumes of material have an adequate heat capacity, and with such necessary tempering the corresponding alteration of the material temperature in such areas can be achieved in the most part by means of heat conduction only. As everybody knows, however the heat conduction increases because of greater temperature differences.
For tempering of corresponding members and tools, respectively, it is common to guide a tempering fluid, such as an adequately temperature controlled liquid, however, in some cases equivalently temperature controlled gases as well, via channels or else a channel system such that cooling or warming can be achieved with that equivalently temperature controlled fluid.
Such channels or channel systems should largely take into account the respective geometry of members and the temperatures which discriminately occur therefore locally. So, the respective volumetric flow rates of the used tempering fluid should be selectively guided into areas of such members or tools wherein increased heat quantity has to be discharged or supplied.
However, the design of such channels or channel systems is very expensive with the fabrication methods being standard for this. Thus, with the fabrication through casting methods such channels/channel systems cannot be formed in any shape and design by means of correspondingly inserted cores. Moreover, minimum wall thicknesses must be kept in order to ensure the required strength.
Because the channels/channel systems are arranged and designed usually inside such members/tools, they can only be manufactured by machining to some extent. So, such members are allowed then to be manufactured by adequately machined component parts which have to be subsequently mounted. At the same time, the joints and joint areas between the parts correspondingly joined together quite often represent a problem since they can also be arranged in critical areas and have to, respectively.
This disadvantage also occurs in particular with members/tools which are assembled of plate-like elements being arranged on top of each other and joined together, quite often also so-called laminates. In this manner, members being designed in the most different way can be manufactured by providing relatively thin-walled plate-like elements with respective apertures wherein such apertures are arranged in adjacent plate-like elements such that adequate channels may be formed by a member/tool manufactured in this way. In this manner, most different geometric shapes and dimensional designs of channels/channel systems can be obtained within members/tools manufactured in this way.
A respective assembly for an injection mold is described in DE 101 51 078 A1.
In this case too, such plate-like elements, indicated therein as lamellas or discs have been arranged on top of each other and joined together. In the plate-like elements, respective apertures which form a cooling channel and a molding cavity as well are designed.
Certainly, the inner contour of the channels due to the plate-like elements is advantageous for required cooling the injection mold as a result of occurring turbulences in the cooling medium, however, the joints between the single plate-like elements have a negative effect with respect to the quality of finish of the workpieces manufactured with it.
This disadvantage can be accepted, if necessary, for particular workpieces which are to be manufactured by plastic injection molding. However, this cannot be tolerated with high-quality workpieces. However, with forming tools, these areas are particularly critical. Thus, during the deformation of the materials for the workpieces to be manufactured, material abrasion and accordingly chip formation can occur.
However, such joint areas are critical not only in the indicated cases but they also have an adverse effect if the respective surface is to be provided with a coating. This is capable to break or even to flake off completely due to the dynamic loads or temperature variations.
With the conventional solutions, tempering elements or tempering systems designed in a complex manner can be used in combination with members/tools, if any, only in an inadequately combined manner.
In most cases, the heat supply and removal, respectively, is too low and afflicted with an increased time constant. So, in particular problems occur with the employments of members/tools within very low or very high temperature ranges or during frequent temperature variations.